<!DOCTYPE html>
<html>

<head>
    <title>圆角</title>
    <meta charset="utf-8">
    <style type="text/css">
    #div1 {
        width: 400px;
        height: 400px;
        border: 1px solid #333;
        border-radius: 0 0 10% 20px;
    }
    </style>
</head>

<body>
    <div id="div1"></div>
</body>

</html>
